/*
Copyright (c) 2007,2007 Elizeu Nogueira da R. Jr.

All rights reserved.

Redistribution and use in source and binary forms, with or without modification, 
are permitted provided that the following conditions are met:

    * Redistributions of source code must retain the above copyright notice, 
      this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above copyright notice, 
      this list of conditions and the following disclaimer in the documentation 
      and/or other materials provided with the distribution.
    * Neither the name of the Elizeu Nogueira da R. Jr. nor the names of its 
      contributors may be used to endorse or promote products derived from this 
      software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.


This package is based on HypersonicSQL, originally developed by Thomas Mueller.
and HSQLDB original developed by the HSQL Development Group
*/

package br.com.dreamsource.mobile.jmesql;

import br.com.dreamsource.mobile.jmesql.exceptions.SQLException;

class Index {
    private String     sName;
    private int	       iFields;
    private int	       iColumn[];
    private int	       iType[];
    private boolean    bUnique;    // just for scripting; all indexes are made unique
    private Node       root;
    private int	       iColumn_0, iType_0;    // just for tuning
    private static int iNeedCleanUp;

    Index(String name, int column[], int type[], boolean unique) {
	sName = name;
	iFields = column.length;
	iColumn = column;
	iType = type;
	bUnique = unique;
	iColumn_0 = iColumn[0];
	iType_0 = iType[0];
    }

    Node getRoot() {
	return root;
    }

    void setRoot(Node r) {
	root = r;
    }

    String getName() {
	return sName;
    }

    boolean isUnique() {
	return bUnique;
    }

    int[] getColumns() {
	return iColumn;    // todo: this gives back also primary key field!
    }

    void insert(Node i) throws SQLException {
	Object  data[] = i.getData();
	Node    n = root, x = n;
	boolean way = true;
	int     compare = -1;

	while (true) {
	    if (Trace.STOP) {
		Trace.stop();
	    }

	    if (n == null) {
		if (x == null) {
		    root = i;

		    return;
		}

		set(x, way, i);

		break;
	    }

	    x = n;
	    compare = compareRow(data, x.getData());

	    Trace.check(compare != 0, Trace.VIOLATION_OF_UNIQUE_INDEX);

	    way = compare < 0;
	    n = child(x, way);
	}

	while (true) {
	    if (Trace.STOP) {
		Trace.stop();
	    }

	    int sign = way ? 1 : -1;

	    switch (x.getBalance() * sign) {

	    case 1:
		x.setBalance(0);

		return;

	    case 0:
		x.setBalance(-sign);

		break;

	    case -1:
		Node l = child(x, way);

		if (l.getBalance() == -sign) {
		    replace(x, l);
		    set(x, way, child(l, !way));
		    set(l, !way, x);
		    x.setBalance(0);
		    l.setBalance(0);
		} else {
		    Node r = child(l, !way);

		    replace(x, r);
		    set(l, !way, child(r, way));
		    set(r, way, l);
		    set(x, way, child(r, !way));
		    set(r, !way, x);

		    int rb = r.getBalance();

		    x.setBalance((rb == -sign) ? sign : 0);
		    l.setBalance((rb == sign) ? -sign : 0);
		    r.setBalance(0);
		}

		return;
	    }

	    if (x.equals(root)) {
		return;
	    }

	    way = from(x);
	    x = x.getParent();
	}
    }

    void delete(Object row[], boolean datatoo) throws SQLException {
	Node x = search(row);

	if (x == null) {
	    return;
	}

	Node n;

	if (x.getLeft() == null) {
	    n = x.getRight();
	} else if (x.getRight() == null) {
	    n = x.getLeft();
	} else {
	    Node d = x;

	    x = x.getLeft();

	    // todo: this can be improved
	    while (x.getRight() != null) {
		if (Trace.STOP) {
		    Trace.stop();
		}

		x = x.getRight();
	    }

	    // x will be replaced with n later
	    n = x.getLeft();

	    // swap d and x
	    int b = x.getBalance();

	    x.setBalance(d.getBalance());
	    d.setBalance(b);

	    // set x.parent
	    Node xp = x.getParent();
	    Node dp = d.getParent();

	    if (d == root) {
		root = x;
	    }

	    x.setParent(dp);

	    if (dp != null) {
		if (dp.getRight().equals(d)) {
		    dp.setRight(x);
		} else {
		    dp.setLeft(x);
		}
	    }

	    if (xp == d) {
		d.setParent(x);

		if (d.getLeft().equals(x)) {
		    x.setLeft(d);
		    x.setRight(d.getRight());
		} else {
		    x.setRight(d);
		    x.setLeft(d.getLeft());
		}
	    } else {
		d.setParent(xp);
		xp.setRight(d);
		x.setRight(d.getRight());
		x.setLeft(d.getLeft());
	    }

	    x.getRight().setParent(x);
	    x.getLeft().setParent(x);

	    // set d.left, d.right
	    d.setLeft(n);

	    if (n != null) {
		n.setParent(d);
	    }

	    d.setRight(null);

	    x = d;
	}

	boolean way = from(x);

	replace(x, n);

	n = x.getParent();

	x.delete();

	if (datatoo) {
	    x.rData.delete();
	}

	while (n != null) {
	    if (Trace.STOP) {
		Trace.stop();
	    }

	    x = n;

	    int sign = way ? 1 : -1;

	    switch (x.getBalance() * sign) {

	    case -1:
		x.setBalance(0);

		break;

	    case 0:
		x.setBalance(sign);

		return;

	    case 1:
		Node r = child(x, !way);
		int  b = r.getBalance();

		if (b * sign >= 0) {
		    replace(x, r);
		    set(x, !way, child(r, way));
		    set(r, way, x);

		    if (b == 0) {
			x.setBalance(sign);
			r.setBalance(-sign);

			return;
		    }

		    x.setBalance(0);
		    r.setBalance(0);

		    x = r;
		} else {
		    Node l = child(r, way);

		    replace(x, l);

		    b = l.getBalance();

		    set(r, way, child(l, !way));
		    set(l, !way, r);
		    set(x, !way, child(l, way));
		    set(l, way, x);
		    x.setBalance((b == sign) ? -sign : 0);
		    r.setBalance((b == -sign) ? sign : 0);
		    l.setBalance(0);

		    x = l;
		}
	    }

	    way = from(x);
	    n = x.getParent();
	}
    }

    Node find(Object data[]) throws SQLException {
	Node x = root, n;

	while (x != null) {
	    if (Trace.STOP) {
		Trace.stop();
	    }

	    int i = compareRowNonUnique(data, x.getData());

	    if (i == 0) {
		return x;
	    } else if (i > 0) {
		n = x.getRight();
	    } else {
		n = x.getLeft();
	    }

	    if (n == null) {
		return null;
	    }

	    x = n;
	}

	return null;
    }

    Node findFirst(Object value, int compare) throws SQLException {
	Trace.assert1(compare == Expression.BIGGER
		     || compare == Expression.EQUAL
		     || compare == Expression.BIGGER_EQUAL,
			"Index.findFirst");

	Node x = root;
	int  iTest = 1;

	if (compare == Expression.BIGGER) {
	    iTest = 0;
	}

	while (x != null) {
	    if (Trace.STOP) {
		Trace.stop();
	    }

	    boolean t = compareValue(value, x.getData()[iColumn_0]) >= iTest;

	    if (t) {
		Node r = x.getRight();

		if (r == null) {
		    break;
		}

		x = r;
	    } else {
		Node l = x.getLeft();

		if (l == null) {
		    break;
		}

		x = l;
	    }
	}

	while (x != null
	       && compareValue(value, x.getData()[iColumn_0]) >= iTest) {
	    if (Trace.STOP) {
		Trace.stop();
	    }

	    x = next(x);
	}

	return x;
    }

    Node first() throws SQLException {
	Node x = root, l = x;

	while (l != null) {
	    if (Trace.STOP) {
		Trace.stop();
	    }

	    x = l;
	    l = x.getLeft();
	}

	return x;
    }

    Node next(Node x) throws SQLException {

	// if(x==null) {
	// return null;
	// }
	if ((++iNeedCleanUp & 127) == 0) {
	    x.rData.cleanUpCache();
	}

	Node r = x.getRight();

	if (r != null) {
	    x = r;

	    Node l = x.getLeft();

	    while (l != null) {
		if (Trace.STOP) {
		    Trace.stop();
		}

		x = l;
		l = x.getLeft();
	    }

	    return x;
	}

	Node ch = x;

	x = x.getParent();

	while (x != null && ch.equals(x.getRight())) {
	    if (Trace.STOP) {
		Trace.stop();
	    }

	    ch = x;
	    x = x.getParent();
	}

	return x;
    }

    private Node child(Node x, boolean w) throws SQLException {
	return w ? x.getLeft() : x.getRight();
    }

    private void replace(Node x, Node n) throws SQLException {
	if (x.equals(root)) {
	    root = n;

	    if (n != null) {
		n.setParent(null);
	    }
	} else {
	    set(x.getParent(), from(x), n);
	}
    }

    private void set(Node x, boolean w, Node n) throws SQLException {
	if (w) {
	    x.setLeft(n);
	} else {
	    x.setRight(n);
	}

	if (n != null) {
	    n.setParent(x);
	}
    }

    private boolean from(Node x) throws SQLException {
	if (x.equals(root)) {
	    return true;
	}

	if (Trace.ASSERT) {
	    Trace.assert1(x.getParent() != null);
	}

	return x.equals(x.getParent().getLeft());
    }

    private Node search(Object d[]) throws SQLException {
	Node x = root;

	while (x != null) {
	    if (Trace.STOP) {
		Trace.stop();
	    }

	    int c = compareRow(d, x.getData());

	    if (c == 0) {
		return x;
	    } else if (c < 0) {
		x = x.getLeft();
	    } else {
		x = x.getRight();
	    }
	}

	return null;
    }

    private int compareRowNonUnique(Object a[],
				    Object b[]) throws SQLException {
	int i = Column.compare(a[iColumn_0], b[iColumn_0], iType_0);

	if (i != 0) {
	    return i;
	}

	for (int j = 1; j < iFields - (bUnique ? 0 : 1); j++) {
	    i = Column.compare(a[iColumn[j]], b[iColumn[j]], iType[j]);

	    if (i != 0) {
		return i;
	    }
	}

	return 0;
    }

    private int compareRow(Object a[], Object b[]) throws SQLException {
	int i = Column.compare(a[iColumn_0], b[iColumn_0], iType_0);

	if (i != 0) {
	    return i;
	}

	for (int j = 1; j < iFields; j++) {
	    i = Column.compare(a[iColumn[j]], b[iColumn[j]], iType[j]);

	    if (i != 0) {
		return i;
	    }
	}

	return 0;
    }

    private int compareValue(Object a, Object b) throws SQLException {
	return Column.compare(a, b, iType_0);
    }

}
